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Efficacy of an alphabaculovirus‐based biological insecticide for control of Chrysodeixis chalcites (Lepidoptera: Noctuidae) on tomato and banana crops
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研究了几种杀虫剂对不同虫龄国槐尺蠖的杀灭效果。结果表明,甲胺磷原液和久效磷原液对高龄幼虫的防治效果更为有效,减退率普遍高于相同条件下对低龄幼虫的防治效果,分别达到95%和96%。 相似文献
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本文报道 AciNPV杀虫剂的生产工艺和安全性检测结果。AciNPV杀虫剂是以多角体制备物加光保护剂和其它助剂,在电动混合筛内混合制备而成。生测证明,丙酮—乳糖共沉样品与病毒杀虫剂对幼虫的致病力很高。其LC_(50)均为2.84×10~3PIB/ml;95%置信限分别为1.70×10~3—4.76×10~3 PIB/ml 或1.43×10~3—5.60×10~3 PIB/ml。 几种粉剂可直接用水和矿物油(如零号柴油)稀释,使用较方便。野外试验表明,防治效果在85%以上。 动物安全性试验表明,该制剂无致病性和致突变作用,对人畜安全。细菌学检测证明,未发现任何与人有关的致病菌,如大肠杆菌、沙门氏菌、志贺菌、弧菌和破伤风杆菌等。 相似文献
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枣步曲幼虫空间分布型及抽样技术的研究 总被引:2,自引:0,他引:2
通过IwaoX-X回归测定,枣步曲幼虫的空间分布为奈曼-A型分布或波松-二项分布,分布的基本成分为致密的个体群,个体群间及个体群内的分布均为随机分布,个体群的面积小于或等于1株树,对于估值抽样提出了两种方案,即整体抽样和层抽样,前者以随机抽样和棋盘式抽样为优,并给出了理论抽样公式,后者以最下层抽样代替整株抽样估计种群密度,可以提高抽样效率,降低抽样费用,且估计精度能达到科研与生产的要求,最后给出I 相似文献
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In 1989, the first recorded outbreak of hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) occurred in New Brunswick, Canada. Data were collected from ten plots established in an area infested from 1992–1994, to assess impacts of hemlock looper. Ocular and branch sample assessments of current defoliation and ocular assessments of total defoliation (all age classes of foliage) were conducted for balsam fir (Abies balsamea [L.] Mill.), white spruce (Picea glauca [Moench] Voss), and black spruce (Picea mariana (Mill.) B.S.P.). Stand response was assessed and related to cumulative defoliation. Ocular assessments were found to accurately estimate defoliation, which was significantly related to tree mortality. Ninety-two percent of balsam fir trees that had cumulative defoliation >90% died. Mortality of balsam fir was significantly (p < 0.05) related to tree size, in both lightly and severely defoliated plots; trees with DBH <11 cm sustained 22–48% higher mortality than larger trees. Mortality of balsam fir, in terms of both percent stems/ha and m3/ha merchantable volume, increased exponentially in relation to three estimates of cumulative (summed) plot mean defoliation. The strongest relationships (r2 = 0.75–0.79) were between mortality and the ocular defoliation assessment for 1990–1993 foliage. Tree mortality caused by the looper outbreak ranged from 4–14% stems/ha in lightly defoliated and from 32–100% in severely defoliated plots; merchantable volume killed was 3–14 m3/ha and 51–119 m3/ha, respectively. Relationships between mortality and defoliation were similar when defoliation was assessed for 1987–1993 and 1990–1993 foliage age classes. 相似文献
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The pale-winged gray moth, Iridopsis ephyraria (Walker), a native geometrid moth species found across eastern North America, has recently caused severe defoliation of eastern hemlock trees, Tsuga canadensis (L.) Carrière, in south-central Nova Scotia, Canada. Field studies were carried out to develop sampling techniques that could be used to predict subsequent defoliation of mature hemlocks, which are too large to sample by conventional methods. Densities of newly emerged, first-instar larvae, estimated by sticky tape traps, explained 77% of the subsequent current-year shoot defoliation by I. ephyraria. Egg densities from foam oviposition traps and mid-instar larval densities from beating sheets were weakly and usually non-significantly related to defoliation. Therefore, foam oviposition traps could be used to qualitatively estimate egg densities of I. ephyraria, but first-instar larvae must be sampled with sticky tape if accurate predictions of hemlock defoliation are desired. 相似文献
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Alternative silvicultural systems were introduced in Coastal Western Hemlock forests of British Columbia, Canada, to reduce
disturbance incurred by conventional clear-cutting and to maintain the forest influence on soil nutrient cycling. As we hypothesized,
in situ pools and net mineralization of NH4
+ were lower under no and low disturbance (old-growth forest and shelterwood) compared to clear-cuts (high disturbance); in
situ pools and net production of NO3
− were very low across all treatments. Gross transformation rates of NH4
+ increased while those of NO3
− decreased with increasing disturbance, suggesting that these processes were uncoupled. We conclude that shelterwood harvesting
reduces the impact on forest floor NH4
+ cycling compared to clear-cutting, and that neither low nor high disturbance intensity results in substantial NO3
− accumulation, as what occasionally occurs in other ecosystems. We hypothesize that the uncoupling of NH4
+ and NO3
− dynamics may be due to the predominance of heterotrophic nitrification by lignin-degrading fungi that oxidize organic N rather
than NH4
+–N, and whose activities are suppressed at high NH4
+ concentrations. 相似文献